Plastic bags have been replacing paper bags in the United States since the 1970s for the grocery and retail products industries due to the superior and inherent moisture resistant properties of plastic. For these industries, these plastic bags usually include integrally connected front and rear wall portions and gussetted side wall portions secured together at the bottoms thereof to define a closed bottom on the bag and at least the front and rear wall portions are open at the top to define a mouth portion on the bag. A majority of these bags have been of the T-shirt type which provide spaced integral handles laterally extending from opposed sides of the open mouth and the top of the bag to provide ease in carrying of the bag by the consumer. However, these plastic bags have also included generally flat top rectangular shaped bags, similar to the prior paper bags without upwardly extending handles, and which may include a handle opening cut through the bag walls in an intermediate portion thereof near the top so that a consumer can grasp and carry the bags through the handle opening. These bags have generally been provided to and used by the grocery and retail product industries in the form of packs of a plurality of such bags and have been mounted on racks for consecutive detachment of the bags from the pack and for holding the bags in an open position for loading before removal from the rack.
One of the major problems encountered with these plastic bag pack and rack systems has been the development of such a system that will adequately and efficiently provide a means for dispensing and loading bags made of ultra-thin plastic material that in many cases are very difficult and cumbersome to work with because of their flexible nature. These problems are compounded in cases where the person filling the bag with grocery or retail products is not trained or familiar with the particular bag/rack system. This was particularly true where the bag/rack system required removal of consecutive bags from a pack mounted on a rack by a central mounting tab and stretching the handles of the removed bag over tabs on arm portions of a rack, such as disclosed in U.S. Pat. No. 4,487,388 assigned to Mobil Oil Corporation.
A major breakthrough with this problem came with the development of the QUIKMATE.RTM. bag/rack system which mounted a pack of thermoplastic grocery bags of the T-shirt type on a rack by a central mounting tab and by apertures in the handles of the bags and which supported consecutive bags frcm the pack on supporting rods or arms on the rack in an open loading position by the apertures in the handles cf the bag on the supporting rods of the rack and for facilitating easy removal of the consecutive loaded bags from the rack, as disclosed in U.S. Pat. No. 4,676,378 assigned to Sonoco Products Company (the assignee of the present application). This QUIKMATE.RTM. bag/rack system allowed consecutive bags to be opened by breaking the central mounting tab on the front wall portion of the bag and pulling the front wall portion of the bag open by sliding the handles having apertures therein along the outwardly extending support rods of the rack for loading of the bags. This QUIKMATE.RTM. system has been very successful in most applications once the user has practiced using the QUIKMATE.RTM. bag/rack system. This system has replaced most of the prior bags/rack systems in the grocery and retail products industries.
However, there are still certain problems with the ease of manual opening of consecutive bags not only with the QUIKMATE.RTM. bag/rack system but also with other bag/rack systems. In that regard, there is a natural tendency for the walls of the flat bags of thermoplastic material to cling together and be difficult to separate, particularly when the bags and bag packs are mounted on a rack and suspended therefrom by central mounting tabs and handle apertures. Others have recognized this problem of manually opening the consecutive bags to overcome the natural tendency of the thermoplastic bag walls to cling to each other by providing so called "front-side-free" or partially "front-side-free" bag constructions, such as disclosed in U.S. Pat Nos. 4,785,938 to Mobil Oil Corporation and 4,796,759 to C.E.E. Compagnie Europeene des Emballages, and published Australian Patent Application No. 79465 of Union Carbide Australia Limited.
These so called "front-side-free" bag constructions were directed to central mounting tabs which were cut free or eliminated entirely on the front panel of the bag; however, these bag constructions still exhibited problems with ease of manually opening of the bags and overcoming the natural tendency of the thermoplastic bag walls to cling together. Accordingly, these so called "front-side-free" bag constructions have not met with any substantial commercial acceptance at this point in time. Moreover, fabrication of these bags is difficult, as may be seen by reference to the aforesaid Australian Patent Application No. 79465 inasmuch as the fabrication process described therein requires the use of a "mouse" inside the tube of thermoplastic film being utilized to fabricate the bag. The term "mouse" in the context of plastic bag manufacturing refers to a device that is free to move inside the tube of film and is trapped in a particular location by the use of rolls or guides and is used generally as an anvil in a cutting operation. This process is complicated and troublesome to run in production and is generally viewed in the industry as not being a viable method for efficient, high speed production of thermoplastic grocery or retail product bag packs, particularly when utilizing ultra-thin gauge materials that are becoming the industry standard.